Problem Solving

   The majority of tomato problems generally stem from 3 things:

      a. Diseases and Pests: some of the most common pathogens are soil-borne, particularly the VFN triad, i.e., Verticillium wilt, Fusarium wilt, Nematodes (AKA eelworms).  There are also visible predators, such as the spectacular hornworm, that treat tomatoes as basically a salad bar thoughtfully provided by growers.
     b. Soil: tomatoes are big eaters.  Therefore, nutrient-poor or -imbalanced soil can lead to a failure to thrive or low fruit production.
     c. Moisture: too much and the roots rot; too little and the plant abandons fruit production in an effort just to survive.  See our blog post of April 21, 2010 for more about the art of watering.
Q: Why are my tomatoes developing squishy areas on the bottom?
A: Blossom-end rot is a "physiological problem caused by a low level of calcium in the fruit itself. "  Read more here at the Gardenweb - Blossom end-rot.  To help heal your soil, amend it freely with calcium-rich items such as:
  • Egg shells
  • Borage - delicious flowers and stems, beloved by bees
Q: What is causing some of the leaves to turn yellow?
A:  Several things may be causing this to happen:
     1. If the lower leaves are yellowing, but not drying, the plant may not be able to get enough nutrtion from the soil.  Therefore, it cannabalizes nutrients from the lower leaves for the growing leaves up top.  In this situation, give the plant a good feed.
     2. If the lower leaves turn yellow and die, the plant may have verticillium or fusarium wilt (see this Ohio State site for more info, pictures).  If this is case, you will need to pull out and discard the affected crop and dirt -- do not put it into your compost bin!  Then, you should do the following:
  • Rotate your crop on a long (4-6 year) cycle
  • Amend the heck out of your soil with liberal amounts of compost and worm castings
     3. If the leaves are turning yellow, and the plant is wilting, nematodes may be the cause.  The best way to tell is to pull up the tomato plant(s) at the end of the season and look for bumpy roots (see example of gall-infested roots).  You will need to heal the soil, which can be done with a combination of:
  • Crop rotation
  • Organic soil amendments, especially ones that encourage microbes that feed on nematodes (see crab shell meal - available from Peaceful Valley Farms
  • Planting french marigolds (Tagetes patula), which contain a natural nematode repellant  
Q: Why are the blooms on my tomato plant dying and falling off?
A: " 'Blossom-Drop' is a condition...where the plant blooms but fails to set fruit as the blooms die and fall off.  ...the most common cause is temperature extremes".  Read more here: Gardenweb - Blossom Drop

Q: What are good companion plants to grow with tomatoes?  What should not be planted with tomatoes
A: With grateful acknowledgement to the late Louise Riotte, we include some advice from "Carrots Love Tomatoes"
  1. Asparagus is an effective killer of nematodes that attack tomatoes. Tomatoes return the favor by repelling asparagus beetles, because tomatoes contain solanine.
  2. Basil helps tomatoes to overcome both insects and disease, also improving growth and flavor.
  3. Garlic sprays are useful in controlling late blight.  Garlic is an effective destroyer of the diseases that damage stone fruits, cucumbers, radishes, spinach, beans, nuts, and tomatoes. Plant garlic with tomatoes against red spider.
  4. Stinging nettle growing nearby improves the keeping qualities of tomatoes.

  1. Tomatoes and anything in the Brassica (Cabbage) family repel each other.
  2. Tomatoes dislike fennel, render potatoes more susceptible to potato blight, and have an inhibiting effect on young apricot trees.
  3. Don't plant tomatoes near corn, since the tomato fruitworm is identical with the corn earworm.